1. Field of the Invention
The present invention relates to a motor, and more particularly to a brushless motor and a method of manufacturing a stator of the brushless motor.
2. Description of the Prior Art
A motor is an apparatus for converting an electric energy to a revolution movement so as to generate the mechanical power.
Generally, motors are classified as an electric motor, a pneumatic motor, and a hydraulic motor. The electric motor has a stator to which permanent magnets are attached for generating a magnetic field, a rotor around which an amateur coil is wound so as to generate a torque thereby rotating, a commutator which supplies the electrical current to the stator and periodically converts an electrical polarity, a rotating shaft which is integrally formed to the rotor for rotating while the rotor is being rotated, and a bearing which supports the rotating shaft for rotating.
When the electrical current is supplied to the electric motor, the electric current is supplied to the amateur coil wound around the rotor. When the electric current flows through the amateur coil, an electric field is generated around the amateur coil. The electric field is applied to a magnetic field so as to create an electromagnetic force. The electromagnetic force rotates the rotor by 90 degrees in a direction based on a Fleming's rule. At this time, the direction of the electric current which flows through the amateur coil is converted into a reverse direction by the rotation of the commutator so that the rotor continuously rotates.
The electric motor is disclosed in a U.S. Pat. No. 4,633,110 (issued to Jerry etc).
FIG. 1 is a plan view showing the conventional electric motor 100. As described in FIG. 1, the electric motor has a stator core 120 around which a coil 130 is wound, a rotor 110 spaced apart from an outer periphery surface of the stator core 120 by a predetermined distance and rotatably mounted, plurality of terminals 140 inserted into a socket 126 formed at a lower portion of the stator core 120 and electrically connected to the coil 130, and P.C.B (not shown).
The stator core 120 is formed at a center portion thereof with a central opening 160, and the rotating shaft 150 penetrates the central opening 160. The rotating shaft 150 is integrally connected to a cup of the rotor 110 so that the rotating shaft 150 rotates while the rotor 110 is being rotated.
The stator core 120 is provided with four main-stator poles 122 and four sub-stator poles 124 formed between the four main-stator poles 122. The coil 130 is respectably wound around the four main-stator poles 122, and the socket 126 is respectably and integrally formed at a lower portion of the four sub-stator poles 124. The socket 126 is formed at an end portion thereof with an opening 126, and an end portion of the plurality of terminals 140 is respectably inserted into the opening 126.
An end portion of the coil 130 is connected to a middle portion of the plurality of terminals 140 by welding so that the coil 130 is electrically connected to the plurality of terminals 140. And, since the plurality of terminals 140 are electrically connected to the P.C.B (not shown), the coil 130 is electrically connected to the P.C.B (not shown). Accordingly, when the electric current is applied to the P.C.B (not shown), the electric current flows the coil 130 through the plurality of terminals 140 so that the magnetic field is created around the stator core 120. The magnetic field is applied to the magnetic field created by the permanent magnetic 112 so as to generate the electromagnetic force. Accordingly, the torque is generated between the rotor 110 and the stator core 120, and the rotor rotates with respect to the stator core 120.
However, in the conventional electrical motor, since the coil having a small diameter is wound around the stator core, it is difficult to uniformly wind the coil around the stator core. Accordingly, it is difficult for the rotating shaft to uniformly rotate by the uniform magnetic field. Furthermore, when the capacity of the motor is increased, the size of the motor is also increased.